#include <stdio.h>
#include <string.h>

void replaceCharacter(char *str, char oldChar, char newChar) {
    for (int i = 0; i < strlen(str); i++) {
        if (str[i] == oldChar) {
            str[i] = newChar;
        }
    }
}

int main() {
    char inputString[] = "1NFORMAT1ON";

    // 文字を置き換える
    replaceCharacter(inputString, '1', 'I');

    // 結果を出力
    printf("Result: %s\n", inputString);

    return 0;
}