A .gitignore

@@ -0,0 +1,2 @@ 
+calc
+calcStatic

A main.cpp

@@ -0,0 +1,89 @@ 
+#include <cstdio>
+
+int checkInput(int argc) {
+    if (argc != 4) printf("%s", "Usage: calc <num1> <op> <num2>\n\n\tOperators: + - x / %\n\tExample: calc 10 / 5\n");
+    return argc != 4;
+}
+
+int getFloat(char* str, float* num) {
+    float iPart = 0;
+    float fPart = 0;
+    int fPartLen = 0;
+    int i = 0;
+    int sign = 1;
+
+    if (str[0] == '-') {
+        sign = -1;
+        i++;
+    }
+
+    while (str[i] != '.') {
+        if (str[i] == '\0') {
+            *num = sign * iPart;
+            return 0;
+        }
+        if (str[i] < '0' || str[i] > '9') return 1;
+        iPart = iPart * 10 + float(str[i]) - '0';
+        i++;
+    }
+    i++;
+    while (str[i] != '\0') {
+        if (str[i] < '0' || str[i] > '9') return 1;
+        fPart = fPart * 10 + float(str[i]) - '0';
+        fPartLen++;
+        i++;
+    }
+    while (fPartLen > 0) {
+        fPart /= 10;
+        fPartLen--;
+    }
+    *num = sign * (iPart + fPart);
+    return 0;
+}
+
+int getInput(char* argv[], float* num1, float* num2, char* op) {
+    if (getFloat(argv[1], num1) || getFloat(argv[3], num2)) {
+        printf("%s", "Error: Invalid number\n");
+        return 1;
+    }
+    *op = argv[2][0];
+    if (*op != '+' && *op != '-' && *op != 'x' && *op != '/' && *op != '%') {
+        printf("%s", "Error: Invalid operator\n");
+        return 1;
+    }
+    return 0;
+}
+
+void calc(float num1, float num2, char op) {
+    switch (op) {
+        case '+':
+            printf("%f\n", num1 + num2);
+            return;
+        case '-':
+            printf("%f\n", num1 - num2);
+            return;
+        case 'x':
+            printf("%f\n", num1 * num2);
+            return;
+        case '/':
+            printf("%f\n", num1 / num2);
+            return;
+        case '%':
+            printf("%d\n", int(num1) % int(num2));
+            return;
+    }
+}
+
+int main(int argc, char* argv[]) {
+    if (checkInput(argc)) return 1;
+
+    float num1 = 0;
+    float num2 = 0;
+    char op = argv[2][0];
+
+    if (getInput(argv, &num1, &num2, &op)) return 1;
+
+    calc(num1, num2, op);
+
+    return 0;
+}