I can't use atoi, need to do it digit by digit.. How do I save it in a int.. given a char* temp put it all in one int..
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <math.h>
int main () {
char* temp = "798654564654564654";
int i = 0;
for (i = 0; i < strlen(temp); i++) {
printf("%d", temp[i] - 48);
}
printf("\n");
}
Like this:
int i = 0, j = 0;
while (temp[j])
i = i*10 + temp[j++] - '0';
However, take to account that your number is very big, so for i
the long long int
type is more appropriate.
#include<string.h>
int main() {
char* s = "798654564654564654";
unsigned long long num = 0;
int i = 0, j = strlen(s);
for(i=0; i< j && s[i]>='0' && s[i]<='9'; i++)
num = num * 10 + s[i] - '0';
printf("%lld",num);
return 0;
}
It should work, Here is a demo .
EDIT : Here is an optimized sol :
unsigned long long latoi(char * s) {
unsigned long long num = 0;
while(*s>='0' && *s<='9') num = num * 10 + *(s++) - '0';
return num;
}
And the demo .
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