Question

How to use the fscanf function to read floats from a file in C

Answer 1

#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>

int main() {
    const char* filename = "d:\\data.txt";

    FILE* fp = fopen(filename, "r");

    if (fp == NULL) {
        fprintf(stderr, "Error open file");
        exit(1);
    }

    float f1, f2, f3, f4 = 0.0f;

    fscanf(fp, "%f %f %f %f", &f1, &f2, &f3, &f4);

    printf("%f %f %f %f\n", f1, f2, f3, f4);
    printf("%.7f %.7f %.7f %.7f\n", f1, f2, f3, f4);
    printf("%.4f %.4f %.4f %.4f\n", f1, f2, f3, f4);
    printf("%.2f %.2f %.2f %.2f\n", f1, f2, f3, f4);

    return 0;
}


// data.txt -> 3.14 8.769 35.2 928.6237



/*
run

3.140000 8.769000 35.200001 928.623718
3.1400001 8.7690001 35.2000008 928.6237183
3.1400 8.7690 35.2000 928.6237
3.14 8.77 35.20 928.62

*/

 

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