[英]How to read data from a text file in C
我有以下文本文件:
ax: 0
ay: -9.8
x: 0
y: 50
vx: 8.66
vy: 6
我只想讀取用於計算的數值。 有沒有辦法忽略字符串,只將值讀取為浮點數?
這是我到目前為止所擁有的:
FILE *fp;
FILE *fr;
fr = fopen("input_data", "rt");
fp = fopen("out_file.txt", "w");
if(fr == NULL) {
printf("File not found");
}
if(fp == NULL) {
printf("File not found");
}
float ax = 0, ay = 0,
x = 0, y = 0,
vx = 0, vy = 0,
time = 0, deltaTime = 0;
fscanf(fr, "%f %f %f %f %f %f %f %f\n",
&ax, &ay, &x, &y, &vx, &vy, &time, &deltaTime);
printf("%f %f %f %f %f %f %f %f\n",
ax, ay, x, y, vx, vy, time, deltaTime);
改用這個:
fscanf(fr, "ax: %f ay: %f x: %f y: %f vx: %f vy: %f", &ax, &ay, &x, &y, &vx, &vy);
在字符串 go 處使用 %s。
示例代碼:
#include <stdio.h>
main()
{
FILE *fp;
FILE *fr;
char junk[100];
fr = fopen("/tmp/x.txt", "rt");
if(fr == NULL){ printf("File not found");}
float ax = 0, ay = 0, x = 0, y = 0, vx = 0, vy = 0, time = 0, deltaTime = 0;
fscanf(fr, "%s %f %s %f %s %f %s %f %s %f %s %f\n", junk, &ax, junk, &ay, junk, &x, junk, &y, junk, &vx, junk, &vy);
printf("%f %f %f %f %f %f\n", ax, ay, x, y, vx, vy);
}
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