Fixed compilation warnings

test_programs/riscv_instructions/boolean_logic/comparisons.c

@@ -9,7 +9,7 @@ int main() {
         } else if (x < y) {
             y += 1;
         } else {
-            return;
+            return 0;
         }
     }
 }

test_programs/riscv_instructions/boolean_logic/switch.c

@@ -1,7 +1,7 @@
 int main() {
     int x = 0;
-    switch(1) {
+    switch(x) {
         case 1: x = 1; break;
-        default: return;
+        default: return 0;
     }
 }

test_programs/riscv_instructions/jump_instructions/jump.c

@@ -1,7 +1,8 @@
 int test() {
-    return 1;
+    return 0;
 }
 
 int main() {
     int x = test();
+    return x;
 }

test_programs/riscv_instructions/simple_arithmetics/unsigned_addition.c

@@ -1,5 +1,5 @@
 // EXPECTS TWO VARIABLES WITH A VALUE OF UNSIGNED 1
-void main() {
+int main() {
     unsigned int x = 0;
     unsigned int y = 1;
     x = x + y;

test_programs/riscv_instructions/simple_arithmetics/unsigned_division.c

@@ -1,5 +1,5 @@
 // Expecting two variables with a value of two
-void main() {
+int main() {
     unsigned int x = 4;
     unsigned int y = 2;
     x = x / y;

test_programs/riscv_instructions/simple_arithmetics/unsigned_multiplication.c

@@ -1,5 +1,5 @@
 // EXPECTS TWO VARIABLES WITH A VALUE OF UNSIGNED 2
-void main() {
+int main() {
     unsigned int x = 1;
     unsigned int y = 2;
     x = x * y;

test_programs/riscv_instructions/simple_arithmetics/unsigned_substraction.c

@@ -1,5 +1,5 @@
 // EXPECTS TWO VARIABLES WITH A VALUE OF UNSIGNED 1
-void main() {
+int main() {
     unsigned int x = 1;
     unsigned int y = 1;
     x = x - y;