C - printf 打印随机字符而不是数组内容

Question

I am making a program that prints the number 0-999 in words, using the if else, or switch, no loops or other complicated stuff. The program prints the integer 433, four hundred forty three. Not just four three three. I've made char arrays of the numbers 1-9 so that I can use such template to make the words correct. I think I'm done and I didn't make any mistakes, I even checked it over and over again. The problem is it doesn't print the array contents. It instead prints random characters like @ M y.

I'm sorry the program is in my native language, satuan means ones, puluhan means tens, and ratusan means hundreds. For example when I input 455, it should output empat ratus lima puluh lima (empat is four and lima is five). but it instead prints @ M y ratus ??!@ puluh ??!@, the characters will be random everytime I try it again.

Can someone tell me what's wrong?

#include <stdio.h>
#include <math.h>

int main()
{
    int input, a, b, c;
    char satuan[100], puluhan[100], ratusan[100];
    scanf("%d", &input);
        c = input%10;
        b = (input%100-(input%10))/10;
        a = input/100;
    if(input==0){
        printf("nol\n");
    }
    else if(input==10){
        printf("sepuluh\n");
    }
    else if(input==11){
        printf("sebelas\n");
    }
    else if(input==12){
        printf("dua belas\n");
    }
    else if(input==13){
        printf("tiga belas\n");
    }
    else if(input==14){
        printf("empat belas\n");
    }
    else if(input==15){
        printf("lima belas\n");
    }
    else if(input==16){
        printf("enam belas\n");
    }
    else if(input==17){
        printf("tujuh belas\n");
    }
    else if(input==18){
        printf("delapan belas\n");
    }
    else if(input==19){
        printf("sembilan belas\n");
    }
    else if(input==101){
        printf("seratus satu\n");
    }
    else if(input==102){
        printf("seratus dua\n");
    }
    else if(input==103){
        printf("seratus tiga\n");
    }
    else if(input==104){
        printf("seratus empat\n");
    }
    else if(input==105){
        printf("seratus lima\n");
    }
    else if(input==106){
        printf("seratus enam\n");
    }
    else if(input==107){
        printf("seratus tujuh\n");
    }
    else if(input==108){
        printf("seratus delapan\n");
    }
    else if(input==109){
        printf("seratus sembilan\n");
    }
    else {

        if(c==1){
        char satuan[100] = {'s','a','t','u'};
        }
        else if(c==2){
        char satuan[100] = {'d','u','a'};
        }
        else if(c==3){
        char satuan[100] = {'t','i','g','a'};
        }
        else if(c==4){
        char satuan[100] = {'e','m','p','a','t'};
        }
        else if(c==5){
        char satuan[100] = {'l','i','m','a'};
        }
        else if(c==6){
        char satuan[100] = {'e','n','a','m'};
        }
        else if(c==7){
        char satuan[100] = {'t','u','j','u','h'};
        }
        else if(c==8){
        char satuan[100] = {'d','e','l','a','p','a','n'};
        }
        else if(c==9){
        char satuan[100] = {'s','e','m','b','i','l','a','n'};
        }


            if(b==1){
            char puluhan[100] = {'s','a','t','u'};
            }
            else if(b==2){
            char puluhan[100] = {'d','u','a'};
            }
            else if(b==3){
            char puluhan[100] = {'t','i','g','a'};
            }
            else if(b==4){
            char puluhan[100] = {'e','m','p','a','t'};
            }
            else if(b==5){
            char puluhan[100] = {'l','i','m','a'};
            }
            else if(b==6){
            char puluhan[100] = {'e','n','a','m'};
            }
            else if(b==7){
            char puluhan[100] = {'t','u','j','u','h'};
            }
            else if(b==8){
            char puluhan[100] = {'d','e','l','a','p','a','n'};
            }
            else if(b==9){
            char puluhan[100] = {'s','e','m','b','i','l','a','n'};
            }


                if(a==1){
                char ratusan[100] = {'s','a','t','u'};
                }
                else if(a==2){
                char ratusan[100] = {'d','u','a'};
                }
                else if(a==3){
                char ratusan[100] = {'t','i','g','a'};
                }
                else if(a==4){
                char ratusan[100] = {'e','m','p','a','t'};
                }
                else if(a==5){
                char ratusan[100] = {'l','i','m','a'};
                }
                else if(a==6){
                char ratusan[100] = {'e','n','a','m'};
                }
                else if(a==7){
                char ratusan[100] = {'t','u','j','u','h'};
                }
                else if(a==8){
                char ratusan[100] = {'d','e','l','a','p','a','n'};
                }
                else if(a==9){
                char ratusan[100] = {'s','e','m','b','i','l','a','n'};
                }
    }

            if(a==0 && b==0){
                printf("%s", satuan);
            }
            else if (a==0){
                printf("%s puluh %s", puluhan, satuan);
            }
            else{
                printf("%s ratus %s puluh %s", ratusan, puluhan, satuan);
            }

    return 0;
}

Answer 1

The problem is, in every if...else condition body, the variable satuan is (re)defined locally, and the scope is only till the end of the body. The variable which you're trying to print, remains uninitialized, and the content of that is indeterminate.

Change the assignments to

 strcpy(satuan, "whatever value");

Answer 2

Lets take, for example, this code here:

if(c==1){
char satuan[100] = {'s','a','t','u'};
}

Here you define a second variable named satuan , inside the scope of the if statement block and only in the scope of the if statement block.

Once this block ends (with the closing } ) this variable ceases to exist, its life-time ends.

This leaves you with the first satuan array, which isn't initialized.

Same with all the other array definitions.

The solutions is to use the existing satuan array, and copy the strings you want to print into it:

if(c==1){
    strcpy(satuan, "satu");
}