Add part-3 testcase runner

Part-3/test.sh

@@ -0,0 +1,25 @@
+# ./test.sh <main.cpp path> <executable file name>
+
+# defining colors
+RED="\033[0;31m"
+GREEN="\033[0;32m"
+CYAN="\033[0;36m"
+NC='\033[0m' # No Color
+
+make clean
+
+counter=0
+for i in {1..6}
+do
+    cp testcases/$i/main.cpp $1/
+    make
+    ./$2 2>&1 | diff testcases/$i/$i.txt -
+    if ! ./$2 2>&1 | diff -rq -B -Z testcases/$i/$i.txt -; then
+        echo -e "${RED}$i - Failed!${NC}"
+    else
+        echo -e "${GREEN}$i - Passed!${NC}"
+        counter=$(( counter + 1 ));
+    fi
+done
+
+echo -e "\n########\t${GREEN}$counter test cases passed!${NC}\t########"